This invention relates generally to the testing of materials or products for tensile strength.
Tensile strength testing of a product or specimen is generally well known. In one form of testing apparatus, the specimen is anchored to a frame and placed under an increasing tensile load by a fluid power mechanism in order to measure and display its tensile strength on some readout display device. The testing apparatus is adjusted to handle a given class of products that fall within an expected range of elastic tensile strength and the load applied during each test operation does not exceed an expected elastic limit. Accordingly, relatively weak products when tested are stressed beyond their elastic limit and sometimes into the plastic region of their tensile stress characteristic causing either permanent set or rupture.
It is therefore an important object of the present invention to prevent unintentional destructive testing of products normal subjected to normal tensile loading in a tension testing operation.